问题
选择题
We cannot figure out ____quite a number of insects, birds, and animals are dying out.
A．that
B．as
C．why
D．when
答案
答案：C
：figure out="understand" by thinking. 理解。从句意看我不明白大量物种正在消亡，缺少状语，排除A、B项。从are dying out的时态排除D项，应该是我不明白大量物种为什么正在消亡。
【标签】名词性从句连接词
